Orange County Leaders Dedicate Groundwater Replenishment System

About 350 business leaders, elected officials and community members from throughout California's Orange County celebrated the launch of the Groundwater Replenishment (GWR) System, the world’s largest advanced water purification project of its kind, on Jan. 25.

The Orange County Water District (OCWD) and the Orange County Sanitation District (OCSD) developed the GWR System jointly. The GWR System takes highly treated sewer water and puts it through a three-step purification process that includes microfiltration, reverse osmosis and ultraviolet light with hydrogen peroxide. The resulting water is near-distilled quality, and is put into Orange County’s groundwater basin.

“The Groundwater Replenishment System serves as a model for public agency collaboration on one of the most significant water projects in California’s history,” said Jim Ferryman, OCSD board chair.

The dedication ceremony featured bipartisan support including speakers Congresswoman Loretta Sanchez (D-Santa Ana) and State Senator and Minority Leader Dick Ackerman (R-Fullerton). After the program, guests toured the new facility and were invited to sample the purified water.

The GWR System generates enough purified water to meet the needs of 500,000 people in northern and central Orange County. The new system has the capacity to produce 70 million gal per day (gpd) of near-distilled quality water. Approximately 35 million gpd is injected into OCWD’s expanded seawater barrier to prevent ocean water from contaminating the groundwater supply. The remaining 35 million gpd are pumped to OCWD’s spreading basins in Anaheim, where it mixes with Santa Ana River water and other imported water sources, and percolates into the groundwater basin.

“The GWR System produces the highest quality water we can put into our groundwater basin, and ensures water reliability for northern and central Orange County at a time when alternative water resources in the state and Colorado River Basin are in jeopardy,” said Steve Sheldon, president of OCWD’s Board of Directors.

Over time, the GWR System will help improve and protect the overall water quality in the groundwater basin by reducing the mineral content and preventing ocean water contamination. It will also provide a reliable, locally controlled supply of water during droughts.